PHYSICAL CONSTRAINT FROM MOVEMENT
Arthrogryposis multiplex congenita due to physical constraint occurs when the capacity of the uterine cavity is small and asymmetric or when the fetus is affected by cutaneous bands that restrict limb movements. The capacity of the uterus may be restricted by oligohydramnios, anatomic malformations, amniotic bands, or uterine tumors. Thick cutaneous bands that restrict fetal joint movements occur in Escobar syndrome.
constellation of findings that occur as the result of decreased amniotic
fluid is called oligohydramnios sequence. The characteristic features
of oligohydramnios sequence are wrinkled skin; skin folds that extend
from the inner canthus to the upper cheek; squashed nose; large, low-set
and posteriorly rotated ears; short neck; and large wrinkled hands. Neonates
may also show scars at skin areas of maximal pressure (Figure 156.1 A).
Arthrogryposis usually involves the knees, feet, wrist and elbow (Figure
156.1 B). The most frequent causes of oligohydramnios are placental insufficiency
and premature rupture of membranes. Bilateral renal agenesis is a rare
but severe cause of oligohydramnios often associated with arthrogryposis.
Figure 156.1.— Arthrogryposis due to physical constrain. [A] scar; [B] arthrogryposis of the wrist.
Neurological disorders should be suspected in any neonate without signs that suggest a cartilaginous abnormality, oligohydramnios sequence, or Escobar syndrome. Neurological abnormalities can be classified based on the region of the nervous system most affected.